Track the default member name for immediate operands.

Usually an instruction firmat has only a single immediate operand called 'imm',
or 'cond' if it is one of the condigtion codes. Add a 'default_member' field to
ImmediateKind to keep track of this default member name in the InstructionData
struct.

meta/cretonne/__init__.py

@@ -237,11 +237,15 @@ variable_args = OperandKind(
 class ImmediateKind(OperandKind):
     """
     The kind of an immediate instruction operand.
+
+    :param default_member: The default member name of this kind the
+                           `InstructionData` data structure.
     """
 
-    def __init__(self, name, doc):
+    def __init__(self, name, doc, default_member='imm'):
         self.name = name
         self.__doc__ = doc
+        self.default_member = default_member
 
     def __repr__(self):
         return 'ImmediateKind({})'.format(self.name)

meta/cretonne/immediates.py

@@ -34,11 +34,16 @@ immvector = ImmediateKind('immvector', 'An immediate SIMD vector.')
 #:
 #: This enumerated operand kind is used for the :cton:inst:`icmp` instruction
 #: and corresponds to the `condcodes::IntCC` Rust type.
-intcc = ImmediateKind('intcc', 'An integer comparison condition code.')
+intcc = ImmediateKind(
+        'intcc',
+        'An integer comparison condition code.',
+        default_member='cond')
 
 #: A condition code for comparing floating point values.
 #:
 #: This enumerated operand kind is used for the :cton:inst:`fcmp` instruction
 #: and corresponds to the `condcodes::FloatCC` Rust type.
 floatcc = ImmediateKind(
-        'floatcc', 'A floating point comparison condition code.')
+        'floatcc',
+        'A floating point comparison condition code.',
+        default_member='cond')